Angie Blannin said that Jac Holmes fought fearlessly against the extremist group and had a “real sense of doing something for the greater good”.

The body of the 24-year-old from Bournemouth will be returned to the UK today, following his death in Raqqa in October while volunteering with the Kurdish People’s Protection Units (YPG).

Oliver Hall, 24, from Portsmouth, who died in November in the city, once the de facto capital of Isis-held territory, will also be returned to the UK.

Blannin told the Today programme on BBC Radio 4 that Holmes, who was just 21 when he first fought against Isis in 2015, originally told her he was going to do “humanitarian” work in the country.

“I knew what was going on over there,” she said, “But I wasn’t that politically astute. I soon realised it was going to be something different to [that]. It was going to be quite dangerous.”

Blannin said she didn’t attempt to change mind because it was already “too late by then”. She added that she thought her son, who had no previous military experience, would do “six months and come home.”

In fact, Holmes, who worked as a sniper, became one of the longest-serving volunteers in the YPG, travelling to Syria three times since August 2015.

He was killed by a suicide bomber days after Raqqa was liberated. Tearfully, Blannin recalled receiving the news that her son had died.

“I’d had this massive relief that he had finally got through got through that hell, that he’d got through three years,” she said.

“This was the point he wanted to get to. That day he was going to leave. I was devastated beyond belief.”

She added that her son “always had the sense of helping the underdog”.